Intracardiac repair of complex heart defects has become routine in great part due to availability of cardiopulmonary bypass(CPB) which has allowed the surgeon to have a direct view of the defect. However, we now recognize that CPB also carries many risks and problems specially in children. Beating heart surgery (without bypass) has been utilized for coronary artery bypass procedures in adults with the advantage of avoiding the adverse effects of CPB. To develop techniques for intracardiac repair of heart defects however, several obstacles need to be overcome:l) development of methods to gain access to intracardiac structures with minimal risk of air emboli or blood loss, 2) ability to obtain high-resolution 3-D images of intracardiac structures in a beating heart, 3) development of instrumentation capable of effecting precise repairs within the confines of the heart chambers, and 4) development of methods to prevent complications including inadvertent injury to cardiac structures. Recent advances in 3-D echocardiography and telerobotics with improved dexterity in small spaces have prompted us to develop techniques for beating heart intracardiac repairs.We will pursue four interrelated aims: AIM I - Develop methods for safely and reliably gaining port access to the atrium on a beating heart. AIM II - Develop and implement imaging techniques necessary to perform port-access intracardiac surgery on a beating heart. AIM Ill - Determine the role of robotic assistance in intracardiac navigation and safe task performance. AIM IV - Characterize the soft tissue biomechanical properties of atrial myocardium related to trans-atrial procedure safety. We will utilize a porcine model of off-pump intracardiac surgery along with in vitro studies to develop and evaluate the various components required to perform beating heart intracardiac procedures safely. To this end, the PI has assembled a multidisciplinary team of investigators with expertise in minimally-invasive cardiovascular surgery, 3-D echocardiography, image-guidance, surgical telerobotics, and myocardial biomechanics.